The present disclosure relates to fluid-cooled copper lids for arc furnaces. Arc furnaces including the copper lid and methods of making and using the same are also disclosed.
Arc furnaces can be used to produce alloys and purified metals, such as copper-beryllium alloys. Electric arc furnaces include a crucible and a set of electrodes. Electrical current arcs between electrodes and through the material contained within the crucible. This current melts the contents of the crucible. This production process can be performed via batch processes or as a continuous process.
In conventional electrical arc furnaces, the crucible is surrounded on its bottom and side (i.e. the hearth) by highly refractory materials. The crucible is then capped with an inner carbon lid and a water-cooled outer lid made of steel. The carbon lid is also refractory (i.e., chemically and physically stable at high temperatures). Despite its high temperature properties, the extremely high temperatures needed to produce copper-beryllium alloys through carbothermic reduction typically requires temperatures of around 3000° F. (˜1650° C.). This leads to excessive wear of the carbon lid, which results in furnace failure and downtime. Both the inner carbon lid and the steel water-cooled lid are also “single use” lids, requiring regular replacement.
The operation of arc furnaces is also constrained by the deterioration of the inner carbon lid and the outer water-cooled steel lid. For example, certain additives cannot be included in the charged material in the crucible, and the furnace cannot be run at higher power, without “eating” away the carbon lid even faster.
It would be desirable to provide lids for arc furnaces that are resistant to deterioration.